BIOCHEMICAL STUDIES ON 2-KETOGULONIC ACID METHYLESTERV. ON THE MECHANISM OF THE FORMATION OF VITAMIN C FROM 2-KETOGULONIC ACID METHYLESTER

摘要

The author has already reported that 2-ketogulonic acid methylester (KGM) has an antiscorbutic action and, in the presence of the extract from plant and animal tissues, SH-compounds, barbituric acid derivatives etc., turn into a Vitamin C-like substance, which, in the author's opinion, is decided as ascorbic acid (AsA) (1-4). If so, what sort of mechanism is at work for the formation of Vitamin C from KGM ? Is the Vitamin C produced directly by enolisation and lactonisation from KGM which may take place ? Or might it be assumed that Vitamin C is formed through some intermediary produced from KGM ? Sasamoto (5) has demonstrated that Vitamin C was produced from mannose via 2, 3-diketogulonic acid (DGA), while Suda (6) verified an increase in the reduction value of indophenol by incubating DGA with liver paste prepared from rabbits or white rats. Sasamoto and Beppu (7), on the other hand, proved this increased reduction value to be the real value of Vitamin C and demonstrated the possibility of the formation of AsA from DGA in vivo. Having been interested in the mechanism for the formation of Vitamin C from KGM, the author has tried the following experiments with a view to throwing some light on the problem.